U.S. patent application number 12/937906 was filed with the patent office on 2011-02-10 for catheter pump for circulatory support.
Invention is credited to Klaus Epple, Oeyvind Reitan.
Application Number | 20110034874 12/937906 |
Document ID | / |
Family ID | 41444758 |
Filed Date | 2011-02-10 |
United States Patent
Application |
20110034874 |
Kind Code |
A1 |
Reitan; Oeyvind ; et
al. |
February 10, 2011 |
CATHETER PUMP FOR CIRCULATORY SUPPORT
Abstract
A catheter pump intended to be inserted in the circulatory
system of a mammal, for example for assisting the heart. The
catheter pump comprises: a hollow catheter (2); a drive cable (1)
arranged in a lumen (6) of the catheter (2); a sheath (3)
surrounding the hollow catheter (2); a drive shaft (5) connected to
a distal end of the drive cable (1) to be rotated by the drive
cable; a propeller (4) arranged at the drive shaft; and a cage (11)
surrounding the propeller. The propeller and the cage are moveable
from a folded position, wherein the catheter pump has a small
cross-sectional dimension of about 3.3 mm to an unfolded position
wherein the unfolded cage surrounds the unfolded propeller and the
size of the cage is about 19.5 mm. The drive shaft comprises a
distal bearing (24) and a proximal bearing (25). A purge system is
arranged for passing fluid in a lumen (7) along the hollow catheter
to the proximal bearing, for purging and lubrication of the
proximal bearing. The fluid is returned outside the drive wire. A
portion of the fluid is passed into channels (22) for passing fluid
from the proximal bearing to the distal bearing, for purging and
lubrication of the distal bearing.
Inventors: |
Reitan; Oeyvind; (Lund,
SE) ; Epple; Klaus; (Rangendingen, DE) |
Correspondence
Address: |
MICHAEL BEST & FRIEDRICH LLP
100 E WISCONSIN AVENUE, Suite 3300
MILWAUKEE
WI
53202
US
|
Family ID: |
41444758 |
Appl. No.: |
12/937906 |
Filed: |
June 22, 2009 |
PCT Filed: |
June 22, 2009 |
PCT NO: |
PCT/SE2009/000318 |
371 Date: |
October 14, 2010 |
Current U.S.
Class: |
604/151 ;
604/131 |
Current CPC
Class: |
A61M 60/135 20210101;
A61M 60/829 20210101; A61M 60/148 20210101; A61M 60/818 20210101;
A61M 60/205 20210101; A61M 60/122 20210101; A61M 60/414
20210101 |
Class at
Publication: |
604/151 ;
604/131 |
International
Class: |
A61M 1/00 20060101
A61M001/00; A61M 37/00 20060101 A61M037/00 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 23, 2008 |
SE |
0801459-9 |
Jun 23, 2008 |
SE |
0801460-7 |
Claims
1-12. (canceled)
13. A catheter pump intended to be inserted in the circulatory
system of a mammal, for example for assisting the heart,
comprising: a hollow catheter; a drive cable arranged in a lumen of
said hollow catheter; a drive shaft connected to a distal end of
the drive cable to be rotated by the drive cable; a proximal
housing and a distal housing arranged at the proximal and distal
ends of the drive shaft; several filaments extending between the
proximal housing and the distal housing, and; a propeller arranged
at the drive shaft between the proximal housing and a distal
housing; further comprising a distal bearing and a proximal bearing
for bearing the drive shaft arranged at the distal housing and
proximal housing; a purge system for passing fluid along the hollow
catheter to said proximal bearing, for purging and lubrication of
said proximal bearing; and channel means being arranged in the
rotating drive shaft for passing fluid from said proximal bearing
to said distal bearing, for purging and lubrication of said distal
bearing.
14. The catheter pump according to claim 13, wherein said drive
shaft is surrounded by a sleeve and said channel means being
arranged between said drive shaft and said sleeve, in the nature of
grooves in the shaft, sleeve, or combination thereof.
15. The catheter pump according to claim 13, wherein said purge
system comprises a dedicated hole in said hollow catheter, which
hole is used solely for the purpose of passing said fluid from the
proximal end of the hollow catheter to the distal end thereof.
16. The catheter pump according to claim 13, wherein said distal
bearing is connected to the surrounding space via a lip seal.
17. The catheter pump according to claim 13, wherein said fluid is
passing outside the drive wire in the said lumen in the direction
from the distal end to the proximal end.
18. The catheter pump according to claim 13, further comprising a
sheath circumventing said hollow catheter and being moveable in the
axial direction for unfolding a cage comprised of several filaments
and propeller blades from a folded position close to said drive
shaft and to an unfolded position.
19. The catheter pump according to claim 13, wherein the propeller
is circumvented by a girdle.
20. The catheter pump according to claim 19, wherein said girdle
comprises an inflateable ring.
21. The catheter pump according to claim 20, wherein said sheath is
moveable a first distance for unfolding said cage and a second
distance for unfolding said propeller blades.
22. A catheter pump intended to be inserted in the circulatory
system of a mammal, for example for assisting the heart,
comprising: a hollow catheter; a sheath surrounding said hollow
catheter and being axially moveable in relation to the hollow
catheter; a drive cable arranged in a lumen of said catheter; a
drive shaft connected to a distal end of the drive cable to be
rotated by the drive cable; a propeller arranged at the drive
shaft; a proximal housing and a distal housing arranged at the
proximal and distal ends of the drive shaft; and several filaments
extending between the proximal housing and the distal housing;
wherein the proximal housing is connected to the hollow catheter
and the distal housing is connected to the shaft, whereby axial
movement of the sheath in relation to the hollow catheter results
in that the distal housing is brought closer to the proximal
housing resulting in that said filaments are unfolded to form a
cage; and the drive shaft comprises a propeller pin arranged so
that said propeller is pivotable between a first folded position,
in which the propeller is parallel with the drive shaft and an
unfolded position in which the propeller is perpendicular to the
drive shaft, whereby the drive shaft is surrounded by a sleeve,
said sleeve comprising actuation pins which are moveable in the
axial direction for cooperation with a cam surface of said
propeller for unfolding the propeller, whereby said axial movement
of the sheath in a first movement unfolds the cage and in a second
subsequent movement the actuation pins of the sleeve act upon the
second cam surface that unfolds the propeller.
23. The catheter pump according to claim 22, further comprising a
spring-loaded bolt arranged for cooperation with cam surfaces of
said propeller.
24. The catheter pump according to claim 10, further comprising a
purge fluid system comprising an axial lumen in said hollow
catheter for providing fluid to a proximal bearing at the proximal
side of the drive shaft; channels in said drive shaft for providing
fluid to a distal bearing at the distal side of the drive shaft;
and a lip seal for passing the fluid from the distal bearing and
out to the surroundings.
Description
AREA OF INVENTION
[0001] The invention relates to a catheter pump intended to be
introduced into the body of a mammal, for example via the femoral
artery and placed in for example the aorta for circulatory support
of the heart. The catheter pump may be arranged after the left
ventricular valve in the aorta or after the right ventricular valve
in the pulmonary artery.
BACKGROUND OF INVENTION
[0002] A previous device for circulatory support is known from U.S.
Pat. No. 5,749,855, having the same inventor as the present
invention. The device comprises a drive cable, with one end of the
drive cable being connectable to a drive source and a collapsible
drive propeller at the other end of the drive cable. The
collapsible drive propeller is adjustable between a closed
configuration in which the collapsible drive propeller is collapsed
on the drive cable and an open configuration in which the
collapsible drive propeller is expanded so as to be operative as an
impeller. A sleeve extends between one side of the collapsible
drive propeller and the other side of the collapsible drive
propeller with the sleeve being movable between configurations in
which the collapsible drive propeller is in the open and closed
configuration.
[0003] A lattice cage is arranged surrounding the propeller and is
folded out at the same time as the propeller.
[0004] This device operates very well in many circumstances.
However, there is still room for improvements. For example, it
would be safer if the lattice cage is folded out before the
propeller is folded out. In addition, the shaft supporting the
propeller needs to be journalled with bearings, and such bearings
need to be lubricated.
[0005] Thus, there is a need in the art for a device addressing
such needs.
SUMMARY OF THE INVENTION
[0006] Accordingly, an object of the present invention is to
mitigate, alleviate or eliminate one or more of the
above-identified deficiencies and disadvantages singly or in any
combination.
[0007] According to an aspect of the invention, there is provided a
catheter pump intended to be inserted in the circulatory system of
a mammal, for example for assisting the heart, comprising: a hollow
catheter; a drive cable arranged in a lumen of said hollow
catheter; a drive shaft connected to a distal end of the drive
cable to be rotated by the drive cable; and a propeller arranged at
the drive shaft; characterized by a distal bearing and a proximal
bearing arranged at the distal end and proximal end of the drive
shaft; a purge system for passing fluid along the hollow catheter
to said proximal bearing, for purging and lubrication of said
proximal bearing; and channel means for passing fluid from said
proximal bearing to said distal bearing, for purging and
lubrication of said distal bearing.
[0008] In an embodiment, the channel means may be arranged in said
drive shaft. The drive shaft may be surrounded by a sleeve and said
channel means may be arranged between said drive shaft and said
sleeve, in the nature of grooves in the shaft and/or sleeve. The
purge system may comprise a dedicated hole in said hollow catheter,
which hole is used solely for the purpose of passing said fluid
from the proximal end of the hollow catheter to the distal end
thereof. The distal bearing may be connected to the surrounding
space via a lip seal. The fluid may pass outside the drive wire in
the said lumen in the direction from the distal end to the proximal
end.
[0009] In another embodiment, there is a sheath circumventing said
hollow catheter and being moveable in the axial direction for
unfolding a cage comprised of several filaments and propeller
blades from a folded position close to said drive shaft and to an
unfolded position. The propeller may be circumvented by a girdle.
The girdle may comprise an inflateable ring. The sheath may be
moveable a first distance for unfolding said cage and a second
distance for unfolding said propeller blades.
[0010] In another aspect, there is provided a catheter pump
intended to be inserted in the circulatory system of a mammal, for
example for assisting the heart, comprising: a hollow catheter; a
sheath surrounding said hollow catheter and being axially moveable
in relation to the hollow catheter; a drive cable arranged in a
lumen of said catheter; a drive shaft connected to a distal end of
the drive cable to be rotated by the drive cable; a propeller
arranged at the drive shaft; a proximal housing and a distal
housing arranged at the proximal and distal ends of the drive
shaft; and several filaments extending between the proximal housing
and the distal housing; characterized in that the proximal housing
is connected to the hollow catheter and the distal housing is
connected to the distal housing, whereby axial movement of the
sheath in relation to the hollow catheter results in that the
distal housing is brought closer to the proximal housing resulting
in that said filaments are unfolded to form a cage; and the drive
shaft comprises a propeller pin arranged so that said propeller is
pivotable between a first folded position, in which the propeller
is parallel with the drive shaft and an unfolded position in which
the propeller is perpendicular to the drive shaft.
[0011] According to an embodiment, the axial movement of the sheath
may in a first movement unfold the cage and may in a second
subsequent movement unfold the propeller. The drive shaft may be
surrounded by a sleeve, said sleeve comprising actuation pins,
which may be moveable in the axial direction for cooperation with a
cam surface of said propeller for unfolding the propeller. A
spring-loaded bolt may be arranged for cooperation with cam
surfaces of said propeller.
[0012] In an embodiment, there may be arranged a purge fluid system
comprising an axial lumen in said hollow catheter for providing
fluid to a proximal bearing at the proximal side of the drive
shaft; channels in said drive shaft for providing fluid to a distal
bearing at the distal side of the drive shaft; and a lip seal for
passing the fluid from the distal bearing and out to the
surroundings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] Further objects, features and advantages of the invention
will become apparent from the following detailed description of
embodiments of the invention with reference to the drawings, in
which:
[0014] FIG. 1A is a schematic view in perspective of a system
according to an embodiment of the invention.
[0015] FIGS. 1B and 1C are cross-sectional views showing the pump
head according to an embodiment of the invention. FIG. 1B shows the
folded pump head during insertion and FIG. 1C shows the pump head
in an unfolded or deployed position.
[0016] FIG. 1D is a cross-sectional view taken line D-D in FIG.
1B.
[0017] FIG. 2A is a perspective view, partly broken, and shows the
deployed distal part of the catheter pump head.
[0018] FIG. 2B is a magnified view of the central part of FIG. 2A
encircled by the circle 2B.
[0019] FIGS. 3A and 3B are cross-sectional views showing the
housing of and the tip and body bearings of the propeller
shaft.
[0020] FIG. 3C is a partially broken view of a portion of FIG.
3A.
[0021] FIG. 4 is a partially broken perspective view showing the
propeller shaft with parts of the sliding outer sleeve removed for
illustrating longitudinal channels on the outer surface of the
propeller shaft.
[0022] FIGS. 5A to 5D are perspective views showing how the
propeller blades are deployed from the folded position to the
unfolded position.
[0023] FIGS. 6A to 6C are partial views showing the unfolding
mechanism in an enlarged scale of the propeller shown in FIGS. 5A
to 5D.
[0024] FIGS. 7 to 12 are perspective and end views showing how the
catheter pump can be used in combination with other treatment
devices and/or diagnostic tools.
DETAILED DESCRIPTION OF EMBODIMENTS
[0025] Below, several embodiments of the invention will be
described with references to the drawings. These embodiments are
described in illustrating purpose in order to enable a skilled
person to carry out the invention and to disclose the best mode.
However, such embodiments do not limit the invention. Moreover,
other combinations of the different features are possible within
the scope of the invention.
[0026] "The Reitan Catheter Pump System" is a temporary circulatory
support system based on the concept of a foldable propeller at the
tip of a flexible catheter according to an embodiment. The system
is used in patients with heart failure when the native heart is
unable to support the body with sufficient oxygenated blood. The
basic principles of the system corresponds to that described in
U.S. Pat. No. 5,749,855 mentioned above.
[0027] There are several blood pumps on the market, but most of
them require major surgery to be implanted. The use of a foldable
propeller has therefore the advantage that while folded during the
insertion it makes it possible to introduce a large dual-winged
propeller with high-flow capacity into the body without the need of
surgery. The propeller is arranged at the distal end of the
catheter in the pump head. In addition to the propeller, the pump
head also comprises a cage made of six filaments surrounding the
propeller in order to protect the aorta against the propeller.
[0028] The insertion is accomplished percutaneously via a puncture
in the femoral artery in the groin through an introducer sheath and
the pump is advanced into the thoracic aorta with the pump head
placed approximately 5 to 10 centimeters below the left subclavian
artery. Once in position, the propeller and its protective cage are
deployed or unfolded. The pump is then ready for operation. The
rotation of the propeller creates a pressure gradient inside the
aorta. The blood pressure decrease created in the upper part of the
aorta facilitates the ejection of blood from the left ventricle.
The increased pressure in the lower part of the aorta facilitates
the perfusion of the internal organs, especially the kidneys.
[0029] The pump is mounted on a flexible catheter with an inner
rotating wire which is connected to a DC motor at the proximal end.
The motor is operated with adjustable rotational speed, monitored
by a specially designed console.
[0030] The pump has a purge system with two small channels, which
transport a 20% glucose solution to the proximal bearing of the
propeller shaft for lubrication an dpurging. Two thirds of this
fluid enters the patient's circulation, and one third of the fluid
is returned to a waste bag. The return fluid passes along the drive
wire, which receives lubrication.
[0031] The advantage of making the system foldable is to be able to
introduce a large propeller into the body without any large
surgery. The size of the folded pump head and the flexible catheter
is approximately 10 French (3.3 mm) in diameter.
[0032] The system comprises four main components:
[0033] 1. The catheter pump head,
[0034] 2. The drive unit,
[0035] 3. The console,
[0036] 4. The purge set.
[0037] The catheter has been designed such that it will be advanced
through the femoral artery into the aorta, so that the pump resides
5 to 10 cm below the subclavian artery in the descending aorta.
[0038] The catheter pump head comprises a flexible outer catheter
or sheath and an inner, hollow catheter, which slide against one
another to deploy the protective cage and unfold the propeller
within the cage. There is a flexible drive wire running through the
central lumen of the inner catheter. The inner catheter also has
two small channels for transporting 20% glucose solution to the
pump head for lubrication and purging. One-third of the fluid is
returned via the internal drive shaft lumen, and two-thirds of the
fluid is added to the blood pool.
[0039] The pump head is mounted at the distal end of the flexible
catheter. Filaments surrounding the propeller are foldable, forming
a protective cage around the propeller when the propeller/cage
system is unfolded. The folded pump head during insertion measures
3.3 mm (10 French), whereas the deployed pump head measures
approximately 19.5 mm. The rotation of the propeller is transmitted
via the flexible drive wire placed in the central lumen of the
inner catheter.
[0040] The proximal end of the catheter (the drive coupling) is
connected via a magnetic field to a DC motor, which is placed in a
Drive Unit. The speed of the DC motor, rotating wire and propeller
is adjustable and is monitored by a console. The speed can be
adjusted between 1,000 and 15,000 rpm.
[0041] The drive unit has been designed such that it may be
positioned at the bedside of the patient and has a magnetic
coupling for connection to the catheter pump at one end. The other
end of the drive unit is connected to the console via an electric
cable.
[0042] The primary functions of the console are to monitor and
control the speed of the catheter pump and a peristaltic pump for
the purge fluid. All controls and monitoring parameters for the
system are displayed on a touch screen. The console also comprises
batteri or electric power for the Drive Unit.
[0043] The purge system is constructed to lubricate and to prevent
entrance of blood into the rotating parts of the pump. The rotation
of the propeller is transmitted from the external DC motor via
magnetic coupling and a flexible wire in the center of the
catheter.
[0044] The purge system consists of small channels inside the
catheter to transport a 20% sterile glucose solution to lubricate
the internal components. Heparin may be added to the purge fluid.
One-third of the fluid is transported back through the inner lumen
and lubricates the rotating wire. Two-thirds of the glucose
solution enters the circulation of the patient and seals off the
drive shaft. The total amount of purge fluid may be set to 600 ml
per 24 hours (about 0.4 ml per minute) and is transported via a
peristaltic pump. The console controls the speed of the peristaltic
pump.
[0045] FIG. 1 discloses an overview of a system according to an
embodiment. The system comprises a catheter A intended to be
introduced into the body of a mammal, such as a human, via the
femoral artery and placed in the aorta for circulatory support of
the heart. The example the femoral artery in the groin and up to
the aortic arc.
[0046] The catheter comprises a pump head with a propeller enclosed
within a cage as described in more details below. The pump head may
be placed in the intra-aortic balloon position in the thoracic
aorta. Other positions may be used as well.
[0047] The other end of the catheter extends at the proximal end
out of the mammal and is connected to a drive unit B, which also
will be further described below. The drive unit B is connected to
and controlled by a control console C, which may comprise
batteries, touch-screen displays and a computer system.
[0048] The distal portion of the catheter, i.e. the pump head, is
shown in FIGS. 1B and 1C. The catheter comprises a drive wire 1
which is flexible and can transmit torque although it can be bent
to some extent. The drive wire 1 is enclosed in an inner, hollow
catheter 2, which in turn is enclosed in an outer catheter or
sheath 3.
[0049] In the present specification, the expression "distal" has
the meaning of facing away from the percutaneous introduction site
and "proximal" has the meaning of being closer to the percutaneous
introduction site than the "distal".
[0050] The drive wire 1, the hollow catheter 2 and the sheath 3
extend along the entire catheter pump, as shown by the cut lines in
FIGS. 1B and 1C.
[0051] The drive wire 1 is at its distal end connected to a drive
shaft 5. A foldable propeller 4 is attached to the shaft in a
folded position shown in FIG. 1B.
[0052] As shown in the cross-sectional view of FIG. 1D, the inner
catheter 2 comprises a cylinder having a central lumen 6, in which
the drive wire 1 is arranged. In addition, the inner catheter 2
comprises two axial holes 7, as will be further described below.
The inner catheter is relatively rigid in the longitudinal
direction and is flexible in the cross-direction. Thus, the
catheter has a sufficient rigidity to be inserted into the vascular
system and moved to a desired position by itself. The catheter has
also a sufficient flexibility to follow the curvature of the
vascular system.
[0053] If a guide wire is used for inserting the catheter pump, the
guide wire may extend inside one of the holes 7.
[0054] The drive wire 1 fits into the central lumen 6 with a small
clearance as shown in FIG. 1D. The clearance may comprise a
lubricant so that the drive wire 1 may rotate freely in the
catheter 2, which is non-rotating. The sheath 3 surrounds the inner
catheter 2 with a clearance. The sheath 3 is moveable in the axial
direction in relation to the inner catheter 2 as will be described
below.
[0055] In the pump head, the distal end of the drive wire 1 is
attached to a nipple 5a arranged at the proximal end of the drive
shaft as shown in FIG. 1B. The drive shaft is journalled in distal
bearings 24 and proximal bearings 25 as shown in FIGS. 1B, 3A and
3B.
[0056] A proximal housing 9 and a distal housing 10 are arranged
adjacent the distal and proximal ends of the drive shaft 5. Several
filaments 11 are arranged between the housing 9 and the housing 10.
In the folded position, the filaments 11 are parallel with the
drive shaft 5 and extend close to the drive shaft as shown in FIGS.
1B and 3C.
[0057] The drive shaft 5 is covered by a sleeve 8, which is
moveable in the axial direction on the drive shaft 5. In the folded
position, the sleeve 8 extends from the proximal housing 9 and ends
a short distance 27 before the distal housing as shown in FIG.
3C.
[0058] The distal housing 10 is attached to the inner catheter 2
and the drive wire 1 via the drive shaft 5. The proximal housing 9
is attached to the outer catheter or sheath 3 as appears from FIG.
2A. The outer catheter 3 is moveable in the axial direction in
relation to the inner catheter 2. When the outer catheter 3 is
moved in the direction downward in FIG. 2A, the proximal housing 9
is advanced towards the distal housing 10 resulting in the fact
that the filaments 11 are bent outward in order to form a cage, as
shown in FIG. 2A. Such bending of the filaments 11 may be
facilitated by weakening lines 26, see FIG. 4, arranged at the
inside of the filaments 11, close to the middle thereof.
[0059] When the cage has been initially formed, continued movement
of the outer catheter 3 and the proximal housing 9 towards the
distal housing 10 results in that the folded propeller is unfolded
to the position shown in FIG. 2A, as further described below in
connection with FIGS. 5A to 5D.
[0060] The cage thus formed, protects the inner walls of a blood
vessel 20 from the propeller. Since the cage is unfolded before the
propeller is unfolded and by the same movement as the unfolding of
the propeller, it is assured that the cage is formed before the
propeller is unfolded. Thus, the blood vessels are protected from
the propeller also during the unfolding of the propeller, which is
an advantage.
[0061] As shown in FIG. 2B, the propeller 4 comprises two blades 4
which are journalled by a propeller pin 13 extending through the
drive shaft 5. Moreover, each propeller blade comprises a cam
surface 12 for cooperation with a spring bolt 14 and an actuation
pin 15 attached to the sleeve 8.
[0062] The complete movement of the outer catheter 3 and the
proximal housing 9 towards the distal housing 10 corresponds to the
short distance 27 shown in FIG. 3C and mentioned above.
[0063] As shown in FIG. 3B, the outer surface of the drive shaft is
provided with several channels 22 extending along the entire drive
shaft inside the sleeve 8.
[0064] A lubricant and purge fluid is introduced into one or both
of the holes 7, see FIG. 1D, at the end of the inner catheter 2
extending out of the body at the percutaneous site. The fluid exits
the hole 7 adjacent the nipple 5a, as shown in FIG. 3B. The fluid,
shown by line 28, encircles the nipple 5a and lubricates the
proximal bearing 25 and passes out to the blood outside the bearing
in order to purge the bearing and prevent blood from entering the
bearing in the opposite direction.
[0065] In addition, the fluid enters the channels 22 and passes
towards the distal housing.
[0066] Moreover, a portion of the fluid is diverted into the
clearance between the inner catheter 2 and the flexible drive wire
1 inside the central lumen 6, as shown in FIG. 1D. This fluid will
lubricate the drive wire and ensure that the drive wire will
operate smoothly. This fluid will return to the percutaneous site
and be collected. The portion of the fluid returning this way is
approximately one third of the total flow.
[0067] The fluid entering the channels 22 at the proximal housing 9
will exit the channels 22 at the distal housing 10 as indicated by
line 29 in FIG. 3A. The fluid will encircle the distal bearing 24
and lubricate the bearing. The fluid will pass outside the sleeve 8
and beyond a lip seal 23 arranged surrounding the sleeve 8. The
sleeve 8 is moveable in relation to the lip seal 23 between the
position shown in FIG. 3C, when the filaments and the propeller are
folded, and the position shown in FIG. 3A, when the propeller and
the cage are unfolded. The fluid finally enters inside the blood
vessel via the lip seal 23 and prevents blood from passing in the
opposite direction.
[0068] Thus, by this arrangement, both the proximal bearing 25 and
the distal bearing 24 are lubricated by the fluid and the fluid
purges the inside of the proximal housing 9 and the distal housing
10 so that no blood can enter inside the housings.
[0069] As shown in FIG. 3C, the channels 22 are open to the
interior of the distal housing also in the folded position of the
cage and propeller. Thus, purge fluid can be provided before
unfolding the cage and propeller and before starting any propelling
action, which is an advantage.
[0070] Alternatively or additionally, the channels 22 can be placed
on the inner surface of the outer sliding sleeve 8 or arranged as
axial holes in the center of the drive shaft. Both the drive shaft
5 and the sleeve 8 are rotating in common.
[0071] With reference now to FIGS. 5A to 5D, the unfolding of the
propeller will be described. The unfolded cage with the filaments
11 is not shown so that the other details will be clearly
visible.
[0072] As appears from FIGS. 5A and 6B, in the folded position of
the propeller blades 4, a spring bolt 14 engages a cam surface 12a
of the propeller blade and keeps the propeller blade in the folded
position. The spring bolt 14 is biased by a spring 16, see FIG.
6B.
[0073] Two actuation pins 15 are arranged at the sleeve 8. When the
sleeve 8 is advanced in the downward direction in order to unfold
the cage, the actuation pins 15 are moved to the position shown in
FIG. 5B, acting upon a second cam surface 12b of the propeller
blade.
[0074] Further movement of the sleeve 8 downward will move the cam
surface 12b downward, thereby pivoting the propeller blade around
the propeller pin 13, as shown in FIGS. 5C and 6A. This action is
counteracted by the spring bolt 14. The spring bolt is forced to
pass over a cam shoulder 12c as shown in FIGS. 5C, 5D and 6A.
[0075] Further movement of the sleeve 8 downward will unfold the
propeller to the position shown in FIG. 2B. The opposite actuation
pin 15 prevents the propeller blade 4 from moving over the 90
degree position.
[0076] When the propeller is fully unfolded, the spring bolt 14 has
lost its contact with the cam surface of the propeller blade, as
appears from FIG. 2B. In this position, the propeller blade is
locked by the actuation pin 15.
[0077] The propeller blade will be retracted to the folded position
at the opposite movement of the actuation pin 15. Then, the cage
will be collapsed to the folded position.
[0078] Thus, it appears that the cage is unfolded or deployed
before the propeller is unfolded. The propeller is unfolded in a
partly or completely deployed cage. This prevents the walls of the
blood vessel from possible sharp edges during the unfolding of the
propeller blades.
[0079] FIG. 7 shows another embodiment of the catheter pump,
wherein the cage is provided with a girdle 17 surrounding the
filaments at the outer positions thereof. This arrangement enables
the addition of a guide wire 18, which may pass the catheter pump
without influencing upon the operation or the pump or contacting
the propeller blades during rotation thereof.
[0080] Alternatively or additionally, a guide tube 19 may be
inserted in a blood vessel 20 and passing the pump head. A
treatment device 21 can be inserted by means of the guide wire 18
and/or the guide tube 19. The treatment device 21 may be a coronary
vessel dilation and stenting device, an ultrasound coronary artery
device, a drug delivery device, a left ventricular pressure
measurement device, a conductance catheter for pressure volume
loops, a catheter for electro-physiology of the left ventricle, a
micro camera, a video camera, a balloon catheter, coronary
angioplasty catheter, etc.
[0081] FIG. 8 is an end view showing the arrangement according to
FIG. 7.
[0082] As shown in FIG. 9, the girdle 17 may be arranged as an
inflatable ring. In this manner, back-flow of blood may be reduces
along the wall of the vessel 20. The flow pattern of the back flow
without such a ring is further illustrated in FIG. 10.
[0083] FIG. 11 shows a catheter pump inserted into the aorta in a
position near the heart. The guide tube 19 extends outside the
catheter pump. The guide tube 19 is inserted with help of the guide
wire 18. The insertion of at least the guide wire 18 may be
accomplished before the insertion of the catheter pump and
deployment of the cage 11. The girdle 17 prevents both the guide
wire 18 as well as the guide tube 19 from coming in contact with
the propeller 4.
[0084] Outside the body, the catheter device A is connected to a
drive unit B as shown in FIG. 1. The drive unit comprises an
electric motor having a radial disk arranged at its shaft. The disk
comprises several permanent magnets attached to the surface of the
disk. The flexible drive wire 1 ends with a similar disk provided
with permanent magnets. The disks of the motor and the disk of the
drive wire are brought into close distance from each other. Then,
the magnets will attract and connect the two disks together. In
this manner, torque from the motor can be transmitted to the drive
wire. If the drive wire is prevented from rotating, for example by
the fact that the propeller is blocked, the magnets of the drive
disks will separate. Then, substantially no torque is transmitted
from the motor, until the motor has been stopped and the magnets of
the disks have been aligned and attract. This is a safety
measure.
[0085] The drive unit B further comprises a peristaltic pump, which
drives the purge fluid into the holes 7 in the inner catheter 2.
The fact that the purge fluid is passing inside a separate channel
to the proximal housing 9 and further to the distal housing 10 is
an advantage. If instead the purge fluid would pass outside the
drive wire, there is a risk that small particles in the drive wire
may come lose and contaminate the bearings.
[0086] The purge fluid passes inside channels 22 arranged in the
drive shaft 5. Thus, no separate member is required between the
proximal housing and the distal housing. The purge fluid has no
other way to escape from the distal housing but via the lip seal
23.
[0087] The catheter pump may be arranged after the left ventricular
valve in the aorta or after the right ventricular valve in the
pulmonary artery. The catheter pump may be arranged adjacent the
heart valves or further down the aorta or artery in any suitable
position.
[0088] The catheter pump may be driven with a constant speed, which
is adjusted to the needs of the patient. If required, the catheter
pump may be driven with a pulsative or partially pulsative flow,
for example substantially synchronously with the heart.
[0089] The catheter pump is intended for assisting the beating
heart. However, the catheter pump may also be used also during
heart surgery when the heart is non-beating.
[0090] Although the present invention has been described above with
reference to specific embodiment, it is not intended to be limited
to the specific form set forth herein. Rather, the invention is
limited only by the accompanying claims and other embodiments than
those specifically described above are equally possible within the
scope of these appended claims.
[0091] In the claims, the term "comprises/comprising" does not
exclude the presence of other elements or steps. Furthermore,
although individually listed, a plurality of means, elements or
method steps may be implemented by e.g. a single unit or process.
Additionally, although individual features may be included in
different claims, these may possibly advantageously be combined,
and the inclusion in different claims does not imply that a
combination of features is not feasible and/or advantageous. In
addition, singular references do not exclude a plurality. The terms
"a", "an", "first", "second" etc do not preclude a plurality.
Reference signs in the claims are provided merely as a clarifying
example and shall not be construed as limiting the scope of the
claims in any way.
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